save request

//...
const requests = {
  get: (url) =>
    superagent.get(`${API_ROOT}${url}`).use(tokenPlugin).then(responseBody),
  post: (url, body) =>
    superagent.post(`${API_ROOT}${url}`).use(tokenPlugin).then(responseBody),
  put: (url, body) =>
    superagent.put(`${API_ROOT}${url}`, body).use(tokenPlugin).then(responseBody)
};
//...
const Auth = {
  // get current user's user object
  current: () => requests.get('/user'),
  // get promise for login success/failure
  login: (email, password) =>
    requests.post('/users/login', {user: {email, password}}),
  register: (username, email, password) =>
    requests.post('/users', {user: {username, email, password}}),
  // put updated user to /user
  save: user =>
    requests.put('/user', { user })
};
// ...